Chronograph-watch with independently mounted chronograph mechanism

ABSTRACT

A CHRONOGRAPH-WATCH WITH THE ELEMENTS OF THE CHRONOGRAPH MECHANISM CARRIED BY A FRAME INDEPENDENTLY OF THE CLOCKWORK.

March 9, 1971 G. DUBQIS ETAL CHRONOGRAPH-WATCH WITH INDEPENDENILY MOUNTED CHRONOGRAPH MECHANISM 4 Sheets-Sheet 1 Filed Sept. 18, 1968 IN VENTORS Gc'ralal DUBOIS Frangof: BERTHOUD ATTORNEY.

March 9, 1971 G. DUBOIS ETAL 3,568,432

CHRONOGRAPH-WATCH WITH INDEPENDENTLY MOUNTED Filed Sept. 18, 1968 CHRONOGRAPH MECHANISM 4 Sheets-Sheet 2 INVENTORS Gmld ouaors Franyois BE RT OUD ATTORNEY.

G. DUBOIS ETAL March 9, 1971 CHRONQGRAPH-WATCH WITH INDEPENDEN'I'LY MOUNTED CHRONOGRAPH MECHANISM Filed Sept. 18, 1968 4 Sheets-Sheet 5 INVENTORS Go'rald DUBOIS Fmnofs BERTHOUD ATTORNEY.

Ma 1971 G. DUBO'IS ETAL 3,568,432

CHRONOGRAPH-WATCH WITH INDEPENDENTLY MOUNTED CHRONOGRAPH MECHANISM Filed Sept. '18, 1968 4 Sheets-Sheet 4 ///m 7 1 8 j l U] l' in //T/////!=LW f/G. I

INVENTORS Ge'rald DUBOIS Francois BEPTHOUD ATTORNEY.

United States Patent 3,568,432 CHRONOGRAPH-WATCH WITH INDEPENDENTLY MOUNTED CHRONOGRAPH MECHANISM Gerald Dubois and Francois Berthoud, Le Lieu, Switzerland, assignors to Dubois & Depraz S.A., Le Lieu, Heuer-Leonidas S.A., Bienne, and G. Leon Breitling S.A., Geneva, Switzerland Filed Sept. 18, 1968, Ser. No. 760,556 Claims priority, application Switzerland, Sept. 22, 1967, 13,386/ 67 Int. Cl. G04f 7/04 US. Cl. 5859 27 Claims ABSTRACT OF THE DISCLOSURE A chronograph-watch with the elements of the chronograph mechanism carried by a frame independently of the clockwork.

The present invention relates to a chronograph-watch characterised by the fact that almost all elements of the chronograph mechanism are carried by an independent frame which is removably secured to the frame of the clockwork.

The drawings show, by way of example, one embodiment of the invention.

FIG. 1 is a plan view of a watch showing the chronograph mechanism in its rest position.

FIG. 2 is a view similar to that of FIG. 1, in the running position of the chronograph.

FIG. 3 is a view similar to FIGS. 1 and 2, in the return to zero position of the chronograph.

FIGS. 4 to 7 are sectional views along lines IVIV, V-V, VIVI, and VII-VII, respectively, of FIG. 2.

FIG. 8 is a sectional view of a detail, at an enlarged scale, and

FIG. 9 is a plan view of a detail, at an enlarged scale.

The chronograph mechanism of the watch represented comprises a frame constituted by a base board 1 and by two bridges 2 and 3 secured to base board 1 by pillars 80 (FIG. 6).

The base board is secured directly to the base plate 81 of the clockwork of the watch by means of pillars 82. One of these pillars 82 is represented in FIG. 8 as passing freely through a hole 83 provided in the gear train bridge 84 of the clockwork.

The axis of the chronograph wheel, designated by 4, carries a chronograph wheel as well as a return-to-zero heart 6. The chronograph wheel 5 is driven, when the chronograph is running, by a driving pinion 7 (FIG. 4), the axis 8 of which is pivotally mounted between gear train bridge 84 of the clockwork and a small bridge 9 secured to a rocking lever 10, hereafter called coupling rocking lever, pivotally mounted on a screw 11 screwed in a pillar 85 carried by the frame of the chronograph (FIG. 7). This coupling rocking lever is submitted to the action of a return spring 12 which urges it into the position represented in FIG. 2 in which the driving pinion 7 is in mesh with the chronograph wheel 5.

The axis 8 of driving pinion 7 carries a second pinion 86 (FIG. 4) in mesh with a driving wheel 87 which constitutes an output of the clockwork, mounted at the extremity of the axis 88 of the driving wheel and pinion ice 89-90 of the clockwork, which extends beyond the gear train bridge 84 of the clockwork.

The second pinion 86 is driven by and continuously in is only in mesh with chronograph wheel 5 when the chronograph is running, the disengagement of driving pinion 7 from chronograph wheel 5 being produced by an oscillating or rocking movement of the axis 8, produced by the movements of the coupling rocking lever 10.

It is to be noted that the toothing of driving pinion 7, as well as the toothing of driving chronograph wheel 5 is very fine, with sharp teeth, permitting an easy coupling of the two elements.

The coupling rocking lever 10, being relatively remote from the base board 1, is carried by two pillars 13 each carrying a screw 14, under the head of which slides the rocking lever. An eccentric abutting member 15, carried by the base board 1, limits the movements of the coupling rocking lever 10 produced by its return spring 12. This abut-ting member allows adjustment of the working position of the coupling rocking lever 10 and, consequently, the degree in which driving pinion 7 is meshing with chronograph wheel 5.

It is to be noted that coupling rocking lever 10, with the elements carried thereby, while taking into account the force exerted thereon by its return spring 12, is balanced with respect to its axis of rotation, so that any lateral shocks sustained would not produce any movement of the rocking lever and, consequently, any coupling of the chronograph. Such an uncoupling would be particularly disturbing, if the shock should occur in a direction substantially perpendicular to the handle of the chronograph, when, in such case, the shock would produce a sudden jump of the handle.

A blade spring 16 acts axially on a shoulder of chronograph wheel axis 4 for producing a friction which prevents any flapping movements of the handle of the chronograph.

The displacements of the coupling rocking lever 10 are produced by the return-to-zero hammer of the chronograph, designated by 17, articulated at 18 on the chronograph frame. This hammer is provided with a heel 17a carrying an eccentric abutting member 19 acting on a shoe-shaped end part 10a, shoe-shaped, of the coupling rocking lever 10, when the chronograph mechanism is in its rest position and in its return-to-zero position, for displacing the coupling rocking lever 10, against the action of its return spring 12 and, thus, uncoupling driving pinion 7 from chronograph wheel 5.

The return-to-zero hammer 17 of the chronograph is rigid with two superposed plates, one of which, designated by 20, constitutes a distance-member, and the other of which, designated by 21, is cut in such a way as to constitute a cam to coact on the one hand with a jumper 22 acting on three bearing surfaces 23, 24 and 25 of this cam, for ensuring the stability of three distinct positions of the return-to-zero hammer, and on the other hand with a rocking lever 26, called the reverse lever, serving to control the displacements of the hammer and acting alternatively on the two bearing surfaces 27 and 28 of the cam 21.

The reverse lever 26 constitutes one of the two elements of a control lever of the return-to-zero hammer, the second element of which is constituted by a sliding member 29, called, control lever, guided by two pins 30 and 31 passing through two elongated apertures 32 and 33,

respectively, of this control lever 29. The push-button which controls the running and the stopping of the chronograph, diagrammatically represented by the arrow 34, acts directly on the control lever 29 for displacing it, by a movement of translation, against the action of a return spring 35.

The extremity of the control lever 29 is provided With a notch 36 in which is engaged a finger 26a of the reverse lever 26, under the action of a return spring 37 acting on a pin 38 carried by the reverse lever, this spring being, on the other side, secured to the control lever 29. Owing to this arrangement, the reverse lever 26 is articulated on the extremity of the control lever 29, while being yieldable by influence of return spring 37 in such a way as to bear on the two end surfaces of the control lever situated on both sides of its notch 36.

A return-to-zero rocking lever 39 is articulated at 40 on the frame of the chronograph. The return-to-zero push-button, represented diagrammatically by the arrow 41, acts on this rocking lever for rotating it in the counter-clockwise direction, against the action of the return spring 35. The return-to-zero rocking lever 39 acts, by its end opposite to its pivotal point, on the cam 21, rigid with the return-to-zero hammer 17, for bringing this latter into the return-to-zero position (FIG. 3) in which its peen, designated by 17!), acts on the return-tozero heart 6 of the chronograph.

It is to be noted that the return-to-zero rocking lever 39 is ended by a nose 39a arranged in such a way as to abut against a portion 21a of cam 21, in case the return-to-zero rocking lever should be operated when the chronograph is running, thus preventing the return-to-zero hammer 17 from being brought into its working position at the wrong time.

Owing to the fact that the abutting bearing surfaces 27 and 28 of cam 21 are situated on both sides of the geometric axis passing through the center of articulation 18 of the cam and through the articulation point of the rocking reverse lever 26 on the control lever 29, the reverse lever acts on the cam for displacing it alternatively in one direction and the other, according to the position in which it lies. When the chronograph is running (FIG. 2), the extremity of the reverse lever 26 acts, when a pressure is exerted on the return-to-zero push-button 41, on the bearing surface 27 of cam 21 for rotating return-to-zero hammer 17 in the clockwise direction, until the extremity of the reverse lever abuts against a circular portion of cam 21 situated between its bearing surfaces 27 and 28, that stops the displacement of the control lever 29 and of the reverse lever 26. The cam 21 and the return-to-zero hammer 17 then occupy their intermediary position corresponding to the stopping of the chronograph.

During this movement of the control lever 29 and of the reverse lever 26, the reverse lever rotates slightly around its point of articulation in the counter-clockwise direction. When the pressure exerted on the push-button 41 is released, the control lever 29 comes back into its initial position, under the effect of its return spring 35. The contact between the extremity of the reverse lever 26 and cam 21 being then broken, the reverse lever is released and comes back, under the action of its return spring 37, into its position in which it bears against the two terminal surfaces of the control lever 29 situated on both sides of the notch 36.

Consequently, if a new pressure is exerted on the pushbutton 41, the reverse lever 26 then acts on the bearing surface 28 of cam 21 for rotating this cam in the counterclockwise direction until it abuts against the circular surface of the cam situated between the two bearing surfaces, thus bringing the chronograph back into its running position.

When a pressure is exerted on the return-to-zero rocking lever 39 While the chronograph is in its rest position (FIG. 1), the extremity of the return-to-zero rocking lever 39 acts on cam 21 for bringing the return-to-zero 4 hammer 17 into its return-to-zero position (FIG. 3), in which the hammer is maintained by the action of the jumper 22 acting on the bearing surface 23 of cam 21.

When the hammer occupies the return-to-zero position, a pressure exerted on the push-button 41 urges the reverse lever 26 to cooperate with the bearing surface 28 of cam 21 for producing the rotation of this cam and, consequently, of the hammer, in the counter-clockwise direction, that lifts the hammer and brings the chronograph back into its running position.

The chronograph mechanism comprises a brake lever 43, articulated on a pillar 44 (FIG. 6), and which is provided with an elastic arm 43a bearing on a pin 45 carried by the base board 1, this arm thus returning resiliently said brake lever into its working position (FIG. 1) in which its portion 46, constituting a shoe, acts radially on the chronograph wheel 5 for stopping it.

When the chronograph is running, a pin 47 carried by the return-to-zero hammer 17 acts on the brake lever 43 for lifting it against the action of its elastic arm or return spring 43a and breaking the contact of its portion 46 with chronograph wheel 5, thus releasing this latter.

When the chronograph is returned to zero, a pin 48 carried by the extremity of the return-to-zero rocking lever 39 acts on the extremity of the brake lever 43 for lifting it and releases chronograph wheel 5, thus permitting return-to-zero hammer 17 to drive freely in rotation the axis of chronograph.

It is to be noted that, once the pressure exerted on the return-to-zero push-button 41 is released, after the return-to-zero operation, the brake lever 43 comes from itself back into its working position under the action of its return spring 430. Consequently, when the chronograph is put in running condition by a pressure exerted on the push-button 41, the brake lever 43 remains in its working position after the part 17b of the return-tozero hammer 17 has left the return-to-zero heart 6, the brake lever being lifted by the pin 47 of the hammer only at the end of the run of this latter, only when the driving of the chronograph is ensured by the meshing of driving pinion 7 with chronograph wheel 5. The synchronisation of the two operations-meshing of driving pinion 7 with chronograph wheel 5 and releasing of this Wheel by the brake lever 43is obtained while rotating the eccentric abutting member 19 constituting the control abutting member of the coupling rocking lever 10.

The chronograph includes a minute counter, running at the rate of one revolution per 30 minutes, the axis 49 of which is pivoted between the base board 1 and the bridge 2 of the chronograph frame, and which extends through a tubular sleeve constituting the axis of rotation of the oscillating mass, eccentrically mounted, of the automatic winding device of the clockwork. This axis 49 carries a counter wheel 50 meshing with a first intermediary wheel 51 rotatably mounted on a rocking lever 52, articulated on an eccentric member 53 carried by the base board 1 of the chronograph frame. This rocking lever 52 is located in a recess 91 provided in the base board 1 (FIGS. 4, 5 and 6). The axis of the chronograph carries a control finger 92 (FIG. 4), the angular position of which is adjustable, acting, once. per revolution, on first intermediary Wheel 51 for driving it for one tooth. The gearing ratio between wheels 50 and 51 being 1:1, counter wheel 50 is also driven step by step, for one tooth, a jumper 54 acting thereon for ensuring the stability of its rest position.

The axis 49 carries a return-to-zero heart 55 with which acts a second part, designated by 17c, of the return-tozero hammer 17.

It is to be noted that a screw 56, with a conical head, screwed in the distance-member 20, acts on part 170, which is slightly resilient, of the hammer 17, for deforming it slightly and thus adjusting exactly its position with respect to the peen 17b.

The chronograph includes a half-hours counter, rotating at the rate of one revolution per 12. hours, the axis 57 of which is pivoted between the base board 1 and the bridge 3 of the chronograph frame (FIG. 5) and which extends through an aperture. provided in a circular ridge shown by the base board 1 of the clockwork, this circular ridge receiving the crown wheel rotatably mounted thereon. The axis 57 carries a wheel 58, with which cooperates a jumper 59 meshing with a wheel 60- carried by an axis 61, also pivoted between the base board 1 and the bridge 3.

The rocking lever 52 carries a second intermediary wheel 62 meshing with the first one, the axis '63 of which carries a control finger '95 acting, once per revolution, on wheel 60. This control finger '95 (FIGS. 5 and 9) is deformable so as its radial position, and consequently its engagement with the toothing of wheel 60, can be adjusted. Its angular position is also adjustable, this finger being rigid with a split hub 95a, frictionally mounted on axis 63 of second intermediary wheel 62.

The gearing ratio between wheels 58 and 60 being 111, the return-to-zero heart of the hours counter, designated by 64 (FIG. 5), with which cooperates a return-to-zero hammer 65, is carried by the axis '61 of wheel 60 and not by axis 57 of the half-hours counter. The return-tozero hammer 65 is articulated at 66 on the chronograph frame and is submitted to the action of a return spring 67 urging it against the return-to-zero heart 64.

This hammer 65 is rigid with a control lever 68 with which cooperates heel 17a of the return-to-zero hammer 17. When this latter occupies its two positions corresponding to the stopping and to the running of the chronograph (FIGS. 1 and 2 respectively), heel 17a acts on control lever 68 against the action of the return spring 67 for maintaining the hammer -65 removed from the returnto-zero heart 64; when the return-to-zero hammer 17 occupies the return-to-zero position (FIG. 3), the control lever 68 is released and the hammer '65 acts on the heart 64 for returning the half-hours counter to zero.

The rocking lever 52 is provided with an arm 52a above which extends the extremity 96a of a small bar 96 secured to the base board 1 by a screw 97 and the purpose of which is, on the one hand, to hold the rocking lever upwardly (FIG. 6) and, on the other hand, to be used as a support for the pillar 44 on which is articulated the brake lever 43. The arm 52a of the rocking lever carries a pin 69 on which bears a return spring 70 urging the extremity of the arm 52a against an eccentric a-buting element 71 (FIGS. 1 and 2). When the rocking lever 52 occupies this position, first intermediary wheel 51 is situated on the way of control finger 92 of the chronograph, so that wheel 51, and consequently the two counters, of minutes and of half-hours, are driven. By adjusting the position of the eccentric abutting member 71, one may vary slightly the working position of the rocking lever 52 and, consequently, the engagement of the control finger 92 of the chronograph with wheel 51. It is to be noted that, in the same way, but while acting on the eccentric member 53, one may displace slightly the point of articulation of the rocking lever 52, thus modifying the engagement of counter wheel 51 with wheel 50. This last adjustment must be effected before the previously mentioned one.

The rocking lever 52 occupies its working position when the chronograph is running or stopped, the chronograph wheel 5 being not driven in this last case. During the return-to-zero operation, the return-to-zero rocking lever 39 operates, by means of a pin 72, an intermediary lever or lever 73, articulated at 74 on the chronograph frame and which acts, by the extremity of a resilient arm 73a of this lever, on a finger 52b of the rocking lever 52 for displacing this latter against the action of its return spring 70 and thus bringing the wheel 51 out of the way of the control finger 92 of the chronograph; likely, in this position, the control finger 95 of the intermediary wheel 62 does not come in contact with wheel 60. Consequently, the return-to-zero of the two counters can be effected while the counters are free, without any risk of a control finger being sprung.

It is to be noted that, when the pressure exerted on the push-button 41 is released, after the return-to-zero operation, the rocking lever comes immediately back to its work position, under the effect of the return spring 70, so that when the return movement of the rocking lever is effected, the hammers are still in contact with the returnto-zero hearts, maintaining strongly the indicators of the counters and of the chronograph, so that there is no risk that the return of the rocking lever produces a displacement of the indicators, as could occur if this return were to be effected while the contact between the hammers and the hearts was already broken.

It is also to be noted that the counters of minutes and of half-hours are situatedon the same frame as the rest of the elements of the chronograph mechanism, all the elements, except for the oscillating driving pinion 7, being thus carried by this frame, while in conventional chronograph mechanisms, the hours and minutes counters are generally mounted on the base plate of the clockwork, on the side thereof facing the dial.

A judicious arangement of the several elements of the chronograph, especially the position of the centers of rotation of the minutes counter 50 of the intermediary wheels 51 and 62 and of the driving wheel 60 of the counter of half-hours, and of wheel 58 of this counter, on a line having the shape of a crescent having for its center the center of the chronograph wheel 5, has permitted this concentration of almost the totality of the elements of the chronograph on the same frame.

What we claim is:

'1. In a chronograph-watch comprising:

(1) a chronograph mechanism,

(2) a clock mechanism,

(3) a frame including a plate removably secured to the clock mechanism,

(4) the elements of the chronograph mechanism being carried by the frame independently of the clock mechanism,

(5) the chronograph mechanism including:

(a) a chronograph wheel,

(b) a minutes counter,

(c) an hours counter,

(d) a rocking lever mounting first and second intermediary wheels,

(e) a first finger,

(f) a second finger,

(6) the first finger rotating with the chronograph wheel for operating the first intermediary wheel in the running position of the chronograph mechanism,

(7) the second intermediary wheel actuating the second finger into operating a supplementary wheel meshing with the hours counter.

2. In the chronograph-watch as set forth in claim 1, the clock mechanism including a base plate and the frame being supported by the base plate of the clock mechanism.

3. In the chronograph-watch as set forth in claim 2, the frame being supported by pillars extending upwardly of the clock mechanism and being secured to the base plate of the clock mechanism.

4. The chronograph-watch according to claim 1 and characterized by the fact that it comprises a braking lever submitted to the action of a return spring which urges it against the chronograph wheel for stopping it, this braking lever being controlled, against the action of its return spring, on the one hand by a return to zero hammer of the chronograph indicator and on the other hand by a return to zero lever controlling this hammer, in such a way that this bra'king lever is put out of service by the return to zero lever when the return to zero is effected and by the hammer when the chronograph is running.

5. The chronograph-watch according to claim 4, the arrangement being such that when the pressure exerted on the return to zero lever is released, the braking lever comes back to its working position under the action of its return spring.

6. In the chronograph-watch as set forth in claim 1, the clock mechanism including a second wheel and pinion and gear train bridge, the axis of the second wheel and pinion extending upwardly of the gear train bridge and carrying a wheel upwardly of the gear train bridge for driving the chronograph mechanism.

7. In the chronograph-watch as set forth in claim 6, with the driving wheel of the chronograph mechanism meshing with a pinion carried by an axis pivoted on the one hand on the gear train bridge of the clock mechanism and on the other hand on a coupling lever for the oscillation of the axis to bring the pinion into engagement with and to separate the pinion from the chronograph driving wheel, all of components of the chronograph mechanism except for the axis being exclusively carried by the frame.

8. In the chronograph-watch according to claim 7, with the upper bearing of the oscillating axis being carried by a bar secured to the coupling lever.

9. In a chronograph-watch according to claim 7, with the coupling lever being controlled by a return-toz ero hammer of the chronograph mechanism.

10. In a chronograph-watch according to claim 7, with the coupling lever being pivoted on a pillar secured to a plate of the frame and bearing on pillars also secured to the plate and held thereon by screws under the head of which it can slide.

11. In a chronograph-watch according to claim 7, with the coupling lever being balanced with respect to its center of rotation for precluding displacement of the coupling lever through lateral shock.

12. In a chronograph-watch according to claim 1, with a return-to-zero hammer of the chronograph mechanism being rigid with a cam cooperant with the control member of the hammer.

13. In a chronograph-watch according to claim 12, with a jumper cooperating with the hammer for main taining the hammer in one of a plurality of stable positions.

14. The chronograph-watch according to claim 1, and characterized by the fact that the spring acting on the reverse lever bears on the control lever.

15. In a chronograph-watch according to claim 12, with the hammer being controlled by a two-part lever with a first part being slidably mounted on the frame and with the other being subject to the action of a return spring for urging it in a determined position with respect to the first part, a cam being provided with two bearing surfaces situated on both sides of the geometrical axis connecting the articulation point of the hammer to the articulation point of the two portions of the lever, whereby, according to the position occupied by the hammer, the reverse lever acts respectively on one or the other of the bearing surfaces for displacing the hammer.

16. Chronograph-watch according to claim 15, displacements of the control lever of the hammer being limited by the reverse lever bearing against a bearing surface of the cam abutting against a surface of the cam situated between the two bearing surfaces of the cam.

'17. The chronograph-watch according to claim 15, and characterized by the fact that the reverse lever acts, when the control lever of the hammer is actuated while the hammer occupies its position corresponding to the running of the chronograph mechanism, on one of the bearing surfaces of the cam for bringing it into an intermediary position Corresponding to the stopping of the chronograph mechanism, with the reverse lever rotating, during the movement of the control lever, around its axis of articulation on the control lever, against the action of its return spring, the return spring returning the reverse lever into its rest position with respect to the control lever as soon as the pressure exerted on the control lever is released, with the reverse lever being then able to act on the second bearing surface of the cam when a new pressure is exerted on the control lever to bring the hammer back into its position corresponding to the running of the chronograph mechanism.

18. The chronograph-watch according to claim 17, a return to zero lever having a portion which encounters the hammer when the lever is operated while the hammer occupies its position corresponding to the running of the chronograph for stopping the return-to-zero lever and preventing its untimely operation.

19. The chronograph-watch according to claim 1, with a sliding gear lever carrying two intermediary wheels meshing one with another and with one being operated when the chronograph mechanism is in running position by a finger rotating with the axis of the chronograph mechanism and the other carrying a finger actuating the hours counter.

20. The chronograph-watch according to claim 19, the driving finger of the hours counter operating an intermediary wheel meshing with the wheel of the hours counter.

21. The chronograph-watch according to claim 20, the operating finger of the hours counter being adjustable radially and angularly with respect to its axis.

22. The chronograph-watch according to claim 20, with the wheel being cooperating with the operating finger of the hours counter rigid with a return to zero heart, and with the gearing ratio between the wheel and the hours counter wheel being 1:1.

23. The chronograph-watch according to claim 19, the sliding gear being partially located in a recess provided in the base board of the frame.

24. The chronograph-watch according to claim 19, the first intermediary wheel of the rocking lever being operated by the finger of the chronograph mechanism and meshing with the wheel of the minutes counter.

25. The chronograph-watch according to claim 24, the sliding gear being pivoted on the frame by means of an eccentric for permitting adjustment of its position for modifying the meshing of the first intermediary wheel with the wheel of the minutes counter.

26. The chronograph-watch according to claim 24, the rocking lever being submitted to the action of a return spring urging it in its position in which the finger of the chronograph axis cooperates with the first intermediary wheel as the rocking lever bears against an eccentric member carried by the frame, and which permits to modify the running position of the rocking lever and, consequently, the engagement of the finger of the chronograph axis with the first intermediary wheel.

27. The chronograph-watch according to claim 24, with the sliding gear being submitted to the action on the one hand of a return spring which urges it in its running position in which the finger of the chronograph axis cooperates with the first intermediary wheel, and on the other hand of an intermediary lever interposed between the rocking lever and a return to zero lever, with the operation of the return to zero lever producing by means of the intermediary lever a displacement of the rocking lever against the action of its return spring, to bring it into a position in which the first intermediary wheel is out of the way of the finger of the chronograph, the return of the rocking lever into its working position being effected as soon as the pressure on the return to zero lever is released, while the return to Zero hammers of the chronograph and counters indicators are still in contact with the return to zero hearts rigid with these indicators to prevent any untimely displacements of the indicators.

References Cited UNITED STATES PATENTS Heuer 58-75 Didisheim 58-76 Buszek et a1 58-59X McMillen 58-74X 10 FOREIGN PATENTS 1/1892 Great Britain 58-74- 7/ 1888 Great Britain 58-74 9/1921 Great Britain 58-76 10/1931 Great Britain 58-74 RICHARD B. WILKINSON, Primary Examiner G. H. MILLER, JR., Assistant Examiner US. Cl. X.R. 

